WO2023119480A1 - Attachment for ultrasonic transducer - Google Patents

Abstract

Provided is an attachment for an ultrasonic transducer which can be used by being changed to a different directional characteristic in accordance with the situation, even if there is only one ultrasonic transducer. An attachment 60 of the present invention, which is attached to an ultrasonic transducer 10, comprises an acoustic lens 81, a holding member 61, and a horizontal maintaining means 71. The acoustic lens 81 has a planar surface 82 and a convex surface 83 positioned on the opposite side to the planar surface 82. The holding member 61 holds the acoustic lens 81 with the planar surface 82 facing upward, and detachably holds the ultrasonic transducer 10 such that an acoustic emission surface 10a is acoustically connected to the planar surface 82. The horizontal maintaining means 71 maintains the ultrasonic transducer 10 and the acoustic lens 81 in a horizontal state.

Description

Attachment for ultrasonic transducer

The present invention relates to an attachment attached to an ultrasonic transducer.

Conventionally, an ultrasonic transducer housing an ultrasonic transducer is suspended by a cable for signal transmission and immersed in water, and an ultrasonic transducer that detects a school of fish by transmitting and receiving ultrasonic waves from the ultrasonic transducer. It has been known. This ultrasonic transducer is used, for example, in ice fishing such as smelt fishing. The ultrasonic transmitter/receiver is inserted into the water through a hole made in the ice during ice fishing.

By the way, there is a demand to adjust (change) the directional characteristics of the ultrasonic waves emitted from the ultrasonic transducer. Conventionally, it has been proposed to use an acoustic lens having a convex surface or a concave surface (see Patent Documents 1 to 5, for example) as a member that changes the directivity of ultrasonic waves.

Japanese Patent Application Laid-Open No. 59-85972 (Figs. 2, 5, 6, etc.) Japanese Patent Application Laid-Open No. 5-212355 (claim 2, paragraphs [0012], [0023], FIG. 1, FIG. 2, etc.) JP-A-10-179582 (paragraph [0017], FIG. 1, etc.) Japanese Patent Application Laid-Open No. 2001-169393 (claims 1, 3, 4, paragraphs [0010], [0016], FIG. 1, FIG. 4, etc.) Japanese Patent Application Laid-Open No. 9-298795 (claim 3, paragraphs [0035], [0037], FIGS. 6 to 8, etc.)

However, in the conventional techniques described in Patent Documents 1 to 5, the acoustic lens is directly attached to the ultrasonic transducer. Therefore, even if the situation changes, there is a problem that the directional characteristics of the ultrasonic waves cannot be changed to a different directional characteristic.

In addition, in order to improve the detection accuracy of the ultrasonic transducer, it is preferable to irradiate (transmit) the ultrasonic wave vertically downward with the acoustic emission surface of the ultrasonic transducer horizontal. The acoustic radiation surface is kept horizontal by the weight of the transducer. However, if the ultrasonic transmitter/receiver is tilted, the acoustic radiation surface is also tilted, so the direction of the irradiated ultrasonic waves is tilted with respect to the vertical direction. In this case, since the school of fish cannot be detected accurately, there is a problem that an error occurs in the display on the fish finder.

The present invention has been made in view of the above problems, and the first object is that even if there is only one ultrasonic transmitter/receiver, it can be used by changing it to a different directional characteristic depending on the situation. To provide an attachment for an ultrasonic transducer. A second object of the present invention is to provide an attachment for an ultrasonic transducer capable of transmitting ultrasonic waves vertically downward and improving detection accuracy by maintaining the ultrasonic transducer horizontally. be.

In order to solve the above-mentioned problems, the invention according to claim 1 is a fish finder in which an ultrasonic transducer that is suspended from a cable and transmits and receives ultrasonic waves is housed in a molded state, and whose bottom surface is an acoustic radiation surface. An attachment attached to an ultrasonic transducer for an aircraft, which holds an acoustic lens having a flat surface and a convex surface located on the opposite side, and the acoustic lens with the flat surface facing upward. a holding member for detachably holding the ultrasonic transducer so that the acoustic radiation surface is acoustically connected to the flat surface of the acoustic lens; The gist thereof is an attachment for an ultrasonic transducer, characterized by comprising a leveling means for keeping an acoustic lens horizontal.

Therefore, according to the first aspect of the invention, the ultrasonic transducer is detachably held by the holding member, and the acoustic lens is arranged on the acoustic radiation surface side of the ultrasonic transducer held by the holding member. be. Therefore, even if there is only one ultrasonic transmitter/receiver, it is possible to change the directional characteristics of the ultrasonic waves emitted from the acoustic radiation surface to different directional characteristics depending on the situation. Specifically, by holding the ultrasonic transmitter/receiver on the holding member, the directional characteristics of the ultrasonic waves can be changed using the acoustic lens. On the other hand, by removing the ultrasonic transmitter/receiver from the holding member, the directivity of the ultrasonic waves can be changed to the original directivity. Moreover, since the ultrasonic transducer and the acoustic lens are horizontally maintained by the horizontal maintenance means, the acoustic radiation surface of the ultrasonic transducer and the flat surface of the acoustic lens are also horizontal. As a result, the ultrasonic waves can be transmitted vertically downward, so that the detection accuracy of the ultrasonic transducer is improved. The convex surface of the acoustic lens may be a spherical surface, a conical surface, or the like.

According to a second aspect of the present invention, there is provided a horizontal maintenance device according to claim 1, wherein the horizontal maintenance means is installed in an opening of a hole provided in the ice, and maintains the ultrasonic transducer and the acoustic lens horizontally. The gist of it is that it is an instrument.

Therefore, according to the second aspect of the invention, the horizontal state of the ultrasonic transducer and the acoustic lens held by the holding member can be adjusted simply by installing the level maintenance device in the opening of the hole provided in the ice. Easy to maintain. In addition, since the horizontality maintaining instrument is supported by solid ice, the horizontal state of the ultrasonic transducer and the acoustic lens can be stably maintained.

The invention according to claim 3 is based on claim 2, wherein the level maintenance device comprises a frame body having a plurality of side portions, and the rod-shaped member connecting the level maintenance device and the holding member is formed by the frame body. and the holding member is arranged inside the frame.

Therefore, according to the third aspect of the invention, since the level maintenance device is composed of a frame having a plurality of sides, the level maintenance device can be used to hold the ice as compared with the case where the level maintenance device is composed of, for example, one side. can be stably installed in the opening of the hole provided in the In addition, since the rod-shaped member that connects the horizontal maintenance device and the holding member is arranged at a position shifted from the center of the frame, the rod-shaped member interferes when attaching and detaching the ultrasonic transducer to and from the holding member. without becoming Furthermore, since the holding member is arranged inside the frame, the ultrasonic transmitter/receiver inserted from the inside of the frame can be easily held by the holding member. The diagonal length of the frame is preferably longer than the inner diameter of the hole provided in the ice. By doing so, it is possible to prevent the leveling instrument from falling into the hole.

The gist of the invention according to claim 4 is that in claim 2 or 3, the horizontal maintenance device is made of a frame body having an even number of sides of 4 or more, and is foldable.

Therefore, according to the fourth aspect of the invention, the horizontal maintenance device (frame body) can be folded compactly, so that the horizontal maintenance device can be easily carried.

The invention according to claim 5 is the invention according to claim 1, wherein the horizontal maintaining means is provided so as to surround the holding member from the outer peripheral side, is made of a material having a specific gravity smaller than that of water, and is made of a material having a specific gravity smaller than that of water. The gist of this is that it is a buoyant body that horizontally maintains the ultrasonic transducer and the acoustic lens.

Therefore, according to the fifth aspect of the invention, since the horizontal maintaining means is a buoyant body provided so as to surround the holding member from the outer peripheral side, the buoyant force acts evenly on the holding member. slope is easily eliminated. As a result, the postures of the ultrasonic transducer and the acoustic lens held by the holding member in water can be easily stabilized, and the acoustic radiation surface of the ultrasonic transducer and the flat surface of the acoustic lens are reliably horizontal. Therefore, the detection accuracy of the ultrasonic transducer can be easily improved.

The invention according to claim 6 is the acoustic lens according to any one of claims 1 to 5, wherein the acoustic lens is detachably held with respect to the holding member, and includes a plurality of types of acoustic lenses having at least one of different dimensions and shapes. The gist of it is that it is selected from acoustic lenses.

Therefore, according to the sixth aspect of the invention, even if there is only one ultrasonic transducer, the acoustic lens selected from a plurality of types of acoustic lenses is held by the holding member according to the situation. The directional characteristics of ultrasonic waves can be switched to various directional characteristics for use.

The invention according to claim 7 is the holding member according to any one of claims 1 to 6, wherein the convex surface side of the acoustic lens with the flat surface facing upward is fitted into the bottom portion of the holding member. The gist of this is that a fitting hole for projecting downward from the bottom surface of the member is provided, and the fitting hole has a shape in which the inner diameter gradually increases as it goes upward.

Therefore, according to the seventh aspect of the invention, since the acoustic lens is held by the holding member in a state in which a part of the convex surface is in surface contact with the inner surface of the fitting hole, the ultrasonic transducer can be placed in the fitting hole. easier to put in.

The invention according to claim 8 is the holding member according to any one of claims 1 to 6, wherein the convex surface side of the acoustic lens with the flat surface facing up is fitted into the bottom portion of the holding member. A fitting hole for projecting downward from the bottom surface of the member is provided, and a mounting fixture is provided which is fixed to the inner peripheral side of the holding member and presses the flat surface of the acoustic lens fitted in the fitting hole. This is the gist of it.

Therefore, according to the eighth aspect of the invention, since the acoustic lens is fixed while being sandwiched between the bottom portion of the holding member and the mounting fixture, the acoustic lens can be securely fixed and held. Therefore, it is possible to solve the problem of the acoustic lens sticking to the ultrasonic transducer and falling into the water when the ultrasonic transducer is lifted.

A ninth aspect of the invention is directed to the holding member according to any one of the first to sixth aspects, wherein the convex surface side of the acoustic lens with the flat surface facing upward is fitted into the bottom portion of the holding member. A fitting hole for projecting downward from the bottom surface of the member, and a water supply/discharge hole for supplying water into the holding member and discharging water from the holding member are provided, and the water supply/discharge hole The gist of this is that the acoustic radiation surface of the ultrasonic transducer and the flat surface of the acoustic lens are acoustically coupled via water, formed by widening a part of the fitting hole.

Therefore, according to the ninth aspect of the invention, when the attachment attached to the ultrasonic transducer is immersed in water, water is supplied into the holding member through the water supply/discharge hole, and the ultrasonic wave is transmitted and received. between the acoustic radiation surface of the instrument and the flat surface of the acoustic lens. As a result, since the ultrasonic transducer and the acoustic lens can be used in close contact with each other through water as a coupling material, the directivity of ultrasonic waves can be made wider than the original directivity. can. Moreover, when the attachment is lifted out of the water, the water can be smoothly discharged to the holding member side through the water supply/discharge hole.

The invention according to claim 10 is based on any one of claims 1 to 9, wherein a groove portion extending in the circumferential direction of the ultrasonic transducer is formed on the outer peripheral surface of the ultrasonic transducer, and the groove portion The gist of this is that the fastening member passing through the holding member is fitted.

Therefore, according to the tenth aspect of the invention, by fitting the fastening member into the groove, it is possible to prevent the ultrasonic transducer and the acoustic lens below it from coming off. It is possible to reliably fix and hold the instrument and the acoustic lens.

As detailed above, according to the inventions described in claims 1 to 10, even if there is only one ultrasonic transducer, it can be used by changing the directional characteristics to different ones depending on the situation. Further, by maintaining the ultrasonic transducer horizontally, it is possible to transmit ultrasonic waves vertically downward, thereby improving the detection accuracy.

1 is a side view showing an ultrasonic transducer of the present invention; FIG. Sectional drawing which shows the attachment for ultrasonic transducers in 1st Embodiment. Similarly, the top view which shows a holding member. 4 is a graph showing the relationship between frequency and directivity angle in Examples 1 and 2 and Comparative Example. 4 is a graph showing the relationship between frequency and transmission/reception sensitivity in Examples 1 and 2 and Comparative Example. Sectional drawing which shows the attachment for ultrasonic transducers in 2nd Embodiment. Similarly, the top view which shows the positional relationship of a holding member and a horizontal maintenance instrument. Sectional drawing which shows the attachment for ultrasonic transducers in other embodiment. Sectional drawing which shows the attachment for ultrasonic transducers in other embodiment. Sectional drawing which shows the attachment for ultrasonic transducers in other embodiment. The top view which shows the positional relationship of a holding member and a horizontal maintenance instrument in other embodiment. The top view which shows the positional relationship of a holding member and a horizontal maintenance instrument in other embodiment. (a) is a plan view showing the positional relationship between a holding member and a horizontal maintenance instrument in another embodiment, and (b) is an explanatory diagram showing a folding method of the horizontal maintenance instrument.

[First embodiment]
BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment embodying the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, the ultrasonic transducer 10 of this embodiment is a device for a fish finder that detects a school of fish existing in water by irradiating ultrasonic waves into water. The ultrasonic transmitter/receiver 10 is used while suspended from a cable 11 . The ultrasonic transmitter/receiver 10 also includes an ultrasonic transducer 12 that transmits and receives ultrasonic waves, and a case 13 that accommodates the ultrasonic transducer 12 in a molded state. Since the ultrasonic transducer 12 of the present embodiment is a composite transducer having a piezoelectric element such as a 0-3 composite structure, a 1-3 composite structure, and a 2-2 composite structure, the phases of the entire radiation surface are compared. It's on target.

The case 13 has a bell shape, and has a lower case 21 forming the lower half of the case 13 and an upper case 22 forming the upper half of the case 13 . The lower case 21 is open at its upper end and has a bottom surface 23 and an outer peripheral surface 24 perpendicular to the bottom surface 23 . The ultrasonic transducer 12 is housed inside the lower case 21 . The outer diameter of the ultrasonic transducer 12 is slightly smaller than the outer diameter of the bottom surface 23 . A bottom surface 23 of the lower case 21 is flat and functions as an acoustic radiation surface 10a for irradiating (transmitting) ultrasonic waves. Further, a groove portion 25 is formed on the outer peripheral surface 24 of the lower case 21 for fitting a screw 114 or the like shown in FIG. The groove portion 25 has a rectangular cross section, extends along the circumferential direction of the cylindrical lower case 21 , and is formed continuously over the entire circumference of the lower case 21 .

As shown in FIG. 1, the upper case 22 has a shape that is open at the lower end and whose outer diameter gradually decreases toward the upper end. A through hole (not shown) for inserting the cable 11 is provided in the upper end portion of the upper case 22 .

It should be noted that the ultrasonic transducer 10 of this embodiment is used in a state of being suspended from the cable 11 during normal use (see FIG. 1). However, the ultrasonic transducer 10 can be used with the attachment 60 (see FIG. 2) attached. Specifically, the attachment 60 includes an acoustic lens 81, a holding member 61, and a buoyancy body 71 (horizontal maintenance means). As shown in FIGS. 2 and 3, the holding member 61 is a substantially cylindrical member made of a resin material such as ABS resin, and is configured in a cup shape by a bottom portion 62, a cylindrical portion 63 and an upper end portion 64. . The holding member 61 detachably holds the ultrasonic transducer 10 so that the acoustic radiation surface 10 a is acoustically connected to the flat surface 82 of the acoustic lens 81 . A space formed by the bottom portion 62 and the cylindrical portion 63 serves as a holding concave portion 65 that holds the ultrasonic transmitter/receiver 10 . The inner diameter of the holding recess 65 (cylindrical portion 63 ) is slightly larger than the outer diameter of the ultrasonic transducer 10 .

Also, one fitting hole 66 is provided in the bottom portion 62 of the holding member 61 . The fitting hole 66 has a circular shape and is provided in the center of the bottom portion 62 . The fitting hole 66 is for fitting the convex surface 83 side of the acoustic lens 81 with the flat surface 82 facing up so as to protrude downward from the bottom surface 61 a (see FIG. 2) of the holding member 61 . At this time, the outer peripheral portion of the acoustic lens 81 is supported from below by the bottom portion 62 . Note that the acoustic lens 81 is detachably held with respect to the holding member 61 . Further, by widening a part of the fitting hole 66, four water supply/discharge holes 67 are formed. Each water supply/discharge hole 67 has a corner portion at a position on the outer peripheral side of the bottom portion 62 . The water supply/discharge holes 67 are arranged at equal angular intervals (90° intervals) with the center C1 (see FIG. 3) of the fitting hole 66 as a reference. Each water supply/discharge hole 67 is for supplying water into the holding recess 65 and discharging the water inside the holding recess 65 to the outside of the holding member 61 .

As shown in FIG. 2, the buoyant body 71 is provided so as to surround the holding member 61 from the outer peripheral side. Specifically, the buoyant body 71 is attached so as to surround the outer wall surface 63a of the cylindrical portion 63 by winding a band plate-like sponge around the entire outer wall surface 63a. The buoyant body 71 is made of a material having a specific gravity smaller than that of water, such as polystyrene foam, polyethylene foam, and polyurethane foam. The buoyant body 71 horizontally maintains the holding member 61, the ultrasonic transmitter/receiver 10, and the acoustic lens 81 by the buoyant force acting on itself. The buoyant body 71 has enough buoyancy that the water surface W1 reaches the flat surface 82 of the acoustic lens 81 when the ultrasonic transducer 10 is not held in the holding recess 65 .

Also, the acoustic lens 81 is a substantially conical member made of urethane resin. On the other hand, the part of the ultrasonic wave transmitter/receiver 10 on the side of the acoustic radiation surface 10a is made of a molding material such as rubber or urethane resin. Therefore, the specific acoustic impedance of the acoustic lens 81 is approximately equal to the specific acoustic impedance of the molding material. The acoustic velocity of ultrasonic waves propagating in the acoustic lens 81 is different from the acoustic velocity of ultrasonic waves propagating through water.

In addition, the acoustic lens 81 has a flat surface 82 and a convex surface 83 located on the opposite side. The outer diameter of the flat surface 82 is larger than the outer diameter of the fitting hole 66 and equal to the outer diameter of the acoustic radiation surface 10a. Therefore, the area of the flat surface 82 is equal to the area of the acoustic radiation surface 10a. Furthermore, the outer diameter of the flat surface 82 is slightly larger than the outer diameter of the ultrasonic transducer 12 housed in the lower case 21 of the ultrasonic transducer 10 . The tip region of the convex surface 83 (the region including the vertex P1 of the acoustic lens 81) is a spherical surface, and the convex surface 83 except for the tip region is an inclined surface. The entire spherical surface forming the convex surface 83 and a part of the inclined surface forming the convex surface 83 project downward from the bottom surface 61 a of the holding member 61 . A part of the inclined surface is supported by the opening end of the fitting hole 66 on the side of the upper surface 61b. Further, the amount of deviation between the central axis O1 (the axis passing through the vertex P1) of the acoustic lens 81 and the central axis O2 of the ultrasonic transducer 10 is 2% or less of the external dimensions of the ultrasonic transducer 10 (this embodiment 0%). If the amount of deviation is greater than 2%, the center of gravity will be biased, and the holding member 61, the ultrasonic transmitter/receiver 10, and the acoustic lens 81 will tilt, and there is a risk that the ultrasonic waves will not travel directly downward.

As shown in FIG. 2, the holding recess 65 of the holding member 61 holds the acoustic lens 81 on the lower side and accommodates and holds the ultrasonic transducer 10 on the upper side. The acoustic lens 81 is arranged on the side of the acoustic radiation surface 10a of the ultrasonic transducer 10, and has a function of changing the directivity of the ultrasonic waves emitted from the acoustic radiation surface 10a.

Next, how to use the attachment 60 for the ultrasonic transducer 10 will be described.

The ultrasonic transducer 10 of this embodiment is used for ice fishing such as smelt fishing. In normal ice fishing, the ultrasonic transducer 10 is immersed in water while suspended by the cable 11 . Fish shoals are detected by transmission and reception of ultrasonic waves by the ultrasonic transducer 12 in the ultrasonic transducer 10 . Specifically, first, the ultrasonic transmitter/receiver 10 and the liquid crystal monitor (not shown) are powered on. Note that the liquid crystal monitor is used while being held by the user, for example. The liquid crystal monitor also has a control device (not shown) that controls the entire device. The control device is composed of a well-known computer comprising a CPU, ROM, RAM and the like.

Next, the CPU of the control device performs control to output an oscillation signal to the ultrasonic transducer 12 in the ultrasonic transducer 10 via the cable 11 to drive the ultrasonic transducer 12 . At this time, the ultrasonic transducer 12 vibrates, and the ultrasonic wave is irradiated (transmitted) from the ultrasonic transducer 12 and the acoustic radiation surface 10a of the ultrasonic transmitter/receiver 10 into the water. Then, when the ultrasonic waves reach the school of fish, the ultrasonic waves are reflected by the school of fish, become reflected waves, propagate toward the ultrasonic transducer 10 , and are input (received) by the ultrasonic transducer 12 . After that, the ultrasonic waves (reflected waves) received by the ultrasonic transducer 12 are converted into received signals and input to the CPU via the cable 11 . At this point, the school of fish is detected. After that, when the user turns off the power, the irradiation of ultrasonic waves and the reception of reflected waves are terminated.

By the way, there is a desire to detect schools of fish in a wider range than usual. In this case, after attaching the attachment 60 to the ultrasonic transmitter/receiver 10, the attachment 60 is used in a state of being immersed in water (see FIG. 2). Specifically, first, the convex surface 83 side of the acoustic lens 81 with the flat surface 82 facing upward is fitted into the fitting hole 66 provided in the holding member 61 . As a result, the acoustic lens 81 is held below the holding recess 65 of the holding member 61 . Next, the ultrasonic transmitter/receiver 10 with the acoustic radiation surface 10 a facing downward is inserted into the holding recess 65 , and the ultrasonic transmitter/receiver 10 is inserted into the fitting hole 66 on the flat surface 82 of the acoustic lens 81 fitted into the fitting hole 66 . place on top. As a result, the ultrasonic transmitter/receiver 10 is accommodated and held in the holding recess 65 , and the attachment 60 is attached to the ultrasonic transmitter/receiver 10 .

Next, put the ultrasonic transducer 10 and the attachment 60 into water. At this time, water enters the holding recessed portion 65 from the four water supply/discharge holes 67 provided in the holding member 61, causing the flat surface 82 of the acoustic lens 81 and the acoustic radiation surface 10a of the ultrasonic transducer 10 to become flat. infiltrate in between. As a result, the flat surface 82 is in close contact (acoustically coupled) to the acoustic radiation surface 10a via the coupling material (here, water). Also, the holding member 61 , the acoustic lens 81 and the ultrasonic transducer 10 float on the water and are maintained horizontally by the buoyant force acting on the buoyant body 71 .

In this state, the CPU of the control device performs control to drive the ultrasonic transducer 12 in the ultrasonic transducer 10 . As a result, the ultrasonic transducer 12 vibrates, and ultrasonic waves are emitted (transmitted) from the acoustic radiation surface 10a of the ultrasonic transducer 10 into the water. The ultrasonic waves emitted from the acoustic emission surface 10a have a wide directivity angle when passing through the acoustic lens 81. FIG. As a result, the directional characteristics of the ultrasonic waves become wider than the original directional characteristics, so that it becomes possible to detect a school of fish in a wider range than usual.

Next, we will explain the attachment evaluation method and its results.

First, a sample for measurement was prepared as follows. An attachment provided with a conical acoustic lens (conical lens) was prepared and used as Example 1 (see "▴" in FIGS. 4 and 5). Also, an attachment provided with a hemispherical acoustic lens (hemispherical lens) was prepared and used as Example 2 (see "●" in Figs. 4 and 5). On the other hand, an attachment without an acoustic lens was prepared and used as a comparative example (see “▪” in FIGS. 4 and 5).

Next, the directional characteristics of ultrasonic waves were verified for each measurement sample (Examples 1 and 2 and Comparative Example). Specifically, ultrasonic waves were emitted from an ultrasonic transducer in the ultrasonic transducer to which the attachment was attached, and the directional characteristics during irradiation (during transmission) were verified. In addition, the frequency was switched in a plurality of steps between 160 kHz and 300 kHz, and ultrasonic waves were applied at each switched frequency. FIG. 4 is a graph showing verification results of the directivity characteristics of ultrasonic waves.

As a result, it was confirmed that in the comparative example in which no acoustic lens was provided, the directional characteristics with a relatively narrow directional angle were obtained at any frequency when ultrasonic waves were emitted from the ultrasonic transducer. On the other hand, in Examples 1 and 2, it was confirmed that when ultrasonic waves were radiated through the acoustic lens, the directivity characteristics had a wider directivity angle than the comparative example at any frequency. In particular, it was confirmed that Example 1, which uses a conical acoustic lens, has a directional characteristic with a wider directivity angle than Example 2, which uses a hemispherical acoustic lens, at all frequencies.

Therefore, it was confirmed that by irradiating ultrasonic waves through an acoustic lens, the directivity angle of the ultrasonic waves is widened and the detection range of the ultrasonic transducer is widened. Furthermore, it was confirmed that the use of a conical acoustic lens widens the directivity angle of the ultrasonic waves and widens the detection range of the ultrasonic transducer.

Next, a voltage is applied to the ultrasonic transducer of each measurement sample (Examples 1 and 2 and Comparative Example), and the voltage is applied on the radiation center axis of the ultrasonic transducer and vertically below the ultrasonic transducer. We obtained the transmit/receive sensitivity at the position of Specifically, first, ultrasonic waves were perpendicularly irradiated (transmitted) to the surface of a reflector located away from the ultrasonic transducer. In addition, the frequency was switched in a plurality of steps between 160 kHz and 300 kHz, and ultrasonic waves were applied at each switched frequency. Then, the ultrasonic waves reflected on the surface of the reflector are received by the ultrasonic transducer after a predetermined time has passed since they were transmitted, and voltage signals are generated at both electrodes of the ultrasonic transducer. Therefore, the voltage amplitude during transmission and reception of the ultrasonic transducer was measured with an oscilloscope, and the transmission/reception sensitivity was calculated based on the results. The results of Examples 1 and 2 and Comparative Example are shown in FIG.

As a result, Examples 1 and 2, which have a wide directivity angle for irradiating ultrasonic waves through an acoustic lens, have lower transmission/reception sensitivity than the comparative example, which has a narrow directivity angle because it does not have an acoustic lens, at all frequencies. was confirmed to be Further, in Examples 1 and 2, Example 1 has a relatively wide directivity angle due to the use of a conical acoustic lens, and Example 2 has a relatively narrow directivity angle due to the use of a hemispherical acoustic lens. It was confirmed that the transmission/reception sensitivity is higher than It was also confirmed that in both Examples 1 and 2 and the comparative example, the transmission/reception sensitivity was maximized when the frequency was 200 kHz. From the above, it has been confirmed that the use of an acoustic lens makes it possible to widen the directivity angle of ultrasonic waves, but lowers the sensitivity. It is considered that a practical level of sensitivity can be obtained by selecting an appropriate material for forming the acoustic lens.

Therefore, the following effects can be obtained in this embodiment.

(1) In the attachment 60 for the ultrasonic transmitter/receiver 10 of the present embodiment, the ultrasonic transmitter/receiver 10 is held in the holding recess 65 of the holding member 61, and the ultrasonic transmitter/receiver 10 held in the holding recess 65 is An acoustic lens 81 is arranged on the side of the acoustic radiation surface 10a. In this case, even if there is only one ultrasonic transmitter/receiver 10, it is possible to change the directional characteristics of the ultrasonic waves emitted from the acoustic radiation surface 10a to different directional characteristics depending on the situation. Specifically, by holding the ultrasonic transmitter/receiver 10 in the holding recess 65 , the directional characteristics (directivity angle) of the ultrasonic waves can be widened using the acoustic lens 81 . On the other hand, by removing the ultrasonic wave transmitter/receiver 10 from the holding recess 65, the directivity of ultrasonic waves can be changed to the original directivity.

In addition, the buoyant body 71 is provided so as to surround the holding member 61 from the outer peripheral side simply by wrapping a strip-shaped sponge around the cylindrical portion 63 of the holding member 61 . For this reason, the ultrasonic transducer 10 and the acoustic lens 81 can be horizontally maintained by the buoyant force acting on the buoyant body 71 without a complicated configuration such as the horizontal maintenance device 41 and the long screw 45 (see FIG. 6). However, the acoustic radiation surface 10a of the ultrasonic transducer 10 and the flat surface 82 of the acoustic lens 81 can be made horizontal. Moreover, even if the surface 3 (see FIG. 6) of the ice 1 is not flat and the horizontal maintenance device 41 cannot be installed, the sound radiation surface 10a and the flat surface 82 can be leveled. As a result, the ultrasonic waves can be transmitted vertically downward, so the detection accuracy of the ultrasonic transmitter/receiver 10 is improved.

(2) In the present embodiment, the buoyant body 71 is provided so as to surround the holding member 61 from the outer peripheral side. easier to be As a result, the postures of the ultrasonic transducer 10 and the acoustic lens 81 held by the holding member 61 can be easily stabilized in water, and the acoustic radiation surface 10a of the ultrasonic transducer 10 and the acoustic lens 81 can be easily stabilized. Since the flat surface 82 is surely horizontal, the detection accuracy of the ultrasonic transducer 10 can be easily improved.

(3) In the present embodiment, the upper case 22 constituting the upper half of the case 13 has a shape that does not get caught, and the groove 25 formed in the lower case 21 constituting the lower half of the case 13 It has a shape that does not protrude from 21 . Therefore, the fishing line is less likely to get entangled in the case 13, particularly during normal ice fishing.

(4) In the present embodiment, since the conical acoustic lens 81 is used as a member for changing the directivity of ultrasonic waves, it is possible to widen the directivity angle compared to, for example, using a hemispherical acoustic lens. (See Figure 4). If the acoustic lens 81 is simply conical, there is a problem that the sensitivity at a position vertically below the acoustic lens 81 on the center axis O1 of the acoustic lens 81 is lowered. Moreover, since it is difficult to form the tip of the cone with high precision, there is also the problem of increased product variation. Therefore, in the present embodiment, since the tip region of the convex surface 83 of the acoustic lens 81 is spherical, these problems can be resolved.

[Second embodiment]
A second embodiment embodying the present invention will be described below with reference to the drawings. Here, the description will focus on the parts that are different from the first embodiment. This embodiment differs from the first embodiment in the structure of the attachment.

Specifically, as shown in FIG. 6, the attachment 30 of this embodiment includes an acoustic lens 81, a holding member 31, and a horizontal maintenance device 41 (horizontal maintenance means). As shown in FIGS. 6 and 7, the holding member 31 is a substantially cylindrical member made of a resin material, and is formed into a cup shape by a bottom portion 32 and a cylindrical portion 33. As shown in FIG. A space formed by the bottom portion 32 and the cylindrical portion 33 serves as a holding recess portion 34 that detachably holds the ultrasonic transmitter/receiver 10 . A substantially cylindrical projecting portion 35 extending in the height direction of the cylindrical portion 33 is projected from the outer wall surface 33 a of the cylindrical portion 33 , and the projecting portion 35 is provided with a screw hole 36 .

In addition, the horizontal maintenance tool 41 is a tool for keeping the holding member 31, the ultrasonic transmitter/receiver 10 and the acoustic lens 81 horizontal. The horizontal maintenance device 41 is installed at the opening of the circular hole 2 provided in the ice 1 (see FIG. 6). The horizontal maintenance device 41 is a plate-like member composed of a substantially annular frame body 42 that contacts the surface 3 of the ice 1 and an overhanging body 43 that overhangs the inner peripheral side of the frame body 42 . Further, the projecting body 43 is provided with a screw insertion hole 44 . Furthermore, as shown in FIG. 7, a horizontal maintenance device 41 and a holding member 41 are positioned at positions deviated from the center C1 of the fitting hole 66 and the center C2 of the frame 42 (in this embodiment, the position where the overhanging body 43 is located). A long screw 45 (bar-shaped member) that connects with the member 31 is arranged. The lower end of the long screw 45 is screwed into the screw hole 36 of the projecting portion 35, and the upper end of the long screw 45 is screwed into and inserted into the screw insertion hole 44 of the projecting body 43, thereby forming a holding member. 31, the ultrasonic transducer 10 and the acoustic lens 81 are maintained horizontally. Further, since the holding member 31 is arranged inside the frame 42 in plan view, the ultrasonic transducer 10 and the acoustic lens 81 held by the holding member 31 are also arranged inside the frame 42 .

Next, how to use the attachment 30 will be explained.

In normal ice fishing, the ultrasonic transducer 10 is immersed in water while suspended by the cable 11. Fish shoals are detected by transmission and reception of ultrasonic waves by the ultrasonic transducer 12 in the ultrasonic transducer 10 .

By the way, there is also a demand for detecting schools of fish in a wider range than usual by fixing the attachment 30 to the ultrasonic transducer 10 and using the attachment 30 in water (see FIG. 6). Specifically, first, the convex surface 83 side of the acoustic lens 81 with the flat surface 82 facing upward is fitted into the fitting hole 66 provided in the holding member 31 . As a result, the acoustic lens 81 is held below the holding recess 34 of the holding member 31 . Next, the ultrasonic transmitter/receiver 10 with the acoustic radiation surface 10 a facing downward is inserted into the holding recess 34 , and the ultrasonic transmitter/receiver 10 is inserted into the fitting hole 66 on the flat surface 82 of the acoustic lens 81 fitted into the fitting hole 66 . place on top. As a result, the ultrasonic transmitter/receiver 10 is accommodated and held in the holding recess 34 , and the attachment 30 is attached to the ultrasonic transmitter/receiver 10 .

Next, the horizontal maintenance device 41 is installed in the opening of the hole 2 provided in the ice 1, and the ultrasonic transducer 10 and the attachment 30 are put into the water. At this time, water enters the holding concave portion 34 from the four water supply/discharge holes 67 provided in the holding member 31, and the flat surface 82 of the acoustic lens 81 and the acoustic radiation surface 10a of the ultrasonic transducer 10 are separated from each other. infiltrate in between. As a result, the flat surface 82 is in close contact (acoustically coupled) to the acoustic radiation surface 10a via the coupling material (here, water).

In this state, the ultrasonic transducer 12 in the ultrasonic transducer 10 is driven to irradiate (transmit) ultrasonic waves from the acoustic radiation surface 10a into the water. The ultrasonic waves emitted from the acoustic emission surface 10a have a wide directivity angle when passing through the acoustic lens 81. FIG. As a result, the directional characteristics of the ultrasonic waves become wider than the original directional characteristics, so that it becomes possible to detect a school of fish in a wider range than usual.

Therefore, according to this embodiment, the following effects can be obtained.

(5) In the attachment 30 for the ultrasonic transducer 10 of the present embodiment, the ultrasonic wave held by the holding member 31 is simply installed in the opening of the hole 2 provided in the ice 1 by simply installing the horizontal maintenance tool 41. The horizontal state of the transducer 10 and the acoustic lens 81 can be easily maintained. In addition, since the level maintenance instrument 41 is supported by the solid ice 1, the horizontal state of the ultrasonic transmitter/receiver 10 and the acoustic lens 81 can be stably maintained.

(6) In this embodiment, since the holding member 31 is arranged inside the frame 42, the ultrasonic transducer 10 (ultrasonic transducer 12) held by the holding member 31 is also inside the frame 42. That is, it is arranged close to the center of the hole 2 provided in the ice 1 . As a result, appropriate fish school detection can be performed directly under the hole 2 .

(7) In the present embodiment, the long screws 45 that connect the horizontal maintenance device 41 and the holding member 31 are arranged at positions shifted from the center C2 of the frame 42 . Therefore, when the ultrasonic transmitter/receiver 10 is attached to and detached from the holding member 31, the long screw 45 does not become an obstacle. Further, the long screw 45 is less likely to be entangled with the cable 11 for suspending the ultrasonic transducer 10, fishing line, or the like.

It should be noted that each of the above embodiments may be modified as follows.

- The acoustic lens 81 of each of the above embodiments has a plurality of types that differ from each other in at least one of the dimensions (e.g., the diameter of the flat surface, the height from the center to the vertex of the flat surface, etc.) and the shape (e.g., the shape of the convex surface, etc.). acoustic lens.

8, a fitting hole 92 for fitting the convex surface 83 side of the acoustic lens 81 with the flat surface 82 up into the holding member 91 and projecting downward from the bottom surface 91a of the holding member 91. , and the fitting hole 92 may be formed so that the inner diameter gradually increases as it goes upward. With this configuration, the acoustic lens 81 is held by the holding member 91 in a state in which a part of the inclined surface forming the convex surface 83 is in surface contact with the inner side surface of the fitting hole 92 , so that the ultrasonic wave is transmitted into the fitting hole 92 . It becomes easy to insert the transducer 10. - 特許庁

The acoustic lens 81 in each of the above embodiments was placed in the holding recesses 34, 65 of the holding members 31, 61, but is fixed to the holding members 31, 61 by fitting or gluing. preferably. If it is not fixed to the holding members 31 and 61, when the ultrasonic transducer 10 is lifted, the attached acoustic lens 81 will be lifted together with the ultrasonic transducer 10, and there is a risk of dropping into the water. because there is

9, an annular mounting fixture 101 is fixed to the inner peripheral side of the holding recess 65 of the holding member 61, and the mounting fixture 101 For example, the peripheral portion of the flat surface 82 of the acoustic lens 81 fitted in the fitting hole 66 is pressed. In this way, the acoustic lens 81 is fixed while being sandwiched between the holding member 61 and the mounting fixture 101, so that the acoustic lens 81 can be reliably fixed and held.

Further, as shown in FIG. 10, a screw 114 (fastening member) is passed through a through-hole 113 provided in a cylindrical portion 112 of a holding member 111, and the tip of the screw 114 passing through the through-hole 113 is used to transmit and receive ultrasonic waves. It may be fitted in a groove 25 formed in the outer peripheral surface 24 of the wave device 10 . In this case, by fitting the screw 114 into the groove 25, it is possible to prevent the case 13 (ultrasonic transducer 10) and the acoustic lens 81 below it from coming off. 10 and the acoustic lens 81 can be reliably fixed and held. Instead of using the screw 114, a permanent magnet may be provided in the groove 25, and a magnetic material such as a metal plate may be provided in the cylindrical portion 112 at a position facing the permanent magnet. Even in this case, the permanent magnets and the metal plate are attracted to each other and are in close contact with each other, so that the case 13 and the acoustic lens 81 can be prevented from coming off. Fixation and holding can be reliably performed. Note that if the screw 114 is not used, the through hole 113 and the groove 25 may not be provided.

- Although the level maintenance instrument 41 of the second embodiment is composed of the substantially annular frame body 42, it may be composed of other shapes. For example, as shown in FIG. 11, leveling device 121 may consist of one strip 122 . The belt-shaped member 122 is provided with a screw insertion hole 44 for screwing and inserting the upper end portion of the long screw 45 .

- Also, as shown in FIG. 12, the horizontal maintenance device 131 may consist of a triangular frame 133 having a plurality of (here, three) sides 132 . Adjacent side portions 132 are connected via shaft portions 134 . A screw insertion hole 44 for screwing and inserting the upper end of a long screw 45 is provided in the central portion of one side portion 132 . In this way, the level maintenance device 131 can be stably attached to the opening of the hole 2 provided in the ice 1, compared to the case where the level maintenance device 131 consists of, for example, one belt-shaped member 122 (see FIG. 11). can be installed.

Further, as shown in FIG. 13( a ), the horizontal maintenance device 141 is composed of a square-shaped frame 143 having an even number of sides 142 of 4 or more (here, 4), and is foldable. good too. The diagonal length of the frame 143 is longer than the inner diameter of the hole 2 provided in the ice 1, and the lengths of the sides 142 are equal to each other. A screw insertion hole 44 for screwing and inserting the upper end of a long screw 45 is provided in the central portion of one side portion 142 .

In this case, for example, as shown in FIG. 13B, two shafts 144 positioned on the diagonal line of a square-shaped frame 143 are rotated so that the adjacent sides 142 overlap each other. For example, the frame 143 is folded into a bar shape. Further, if the frame 143 folded into a rod shape is rotated around the shaft 144 positioned in the center so that the side portions 142 positioned on both sides of the shaft 144 overlap each other, the frame 143 can be folded in half. Folded to length. As a result, the level maintenance tool 141 (frame body 143) can be folded compactly, so that the level maintenance tool 141 can be easily carried.

· In the second embodiment, the long screw 45 is used as the rod-shaped member, but a metal rod or the like without thread grooves may be used as the rod-shaped member.

- Four water supply/discharge holes 67 were provided in the bottoms 32, 62 of the holding members 31, 61 in each of the above embodiments, but the number of water supply/discharge holes 67 may be five or more, or three. It may be one or less, or it may not be provided. Also, the water supply/discharge hole 67 is formed by widening a part of the fitting hole 66 , but it may be a hole independent of the fitting hole 66 .

- In each of the above-described embodiments, the case 13 of the ultrasonic transducer 10 is formed by joining the upper case 22 and the lower case 21, but the case is integrally formed. good too.

· The attachments 30 and 60 of the above-described embodiments are used for fish finders, but may be used for measuring instruments such as depth sounders for measuring the depth of water.

Next, in addition to the technical ideas described in the claims, technical ideas grasped by the above-described embodiments are listed below.

(1) In any one of claims 1 to 10, the amount of deviation between the central axis of the acoustic lens and the central axis of the ultrasonic transducer is 2% or less of the outer diameter of the ultrasonic transducer. An attachment for an ultrasonic transducer, characterized in that it has a size of

(2) In claim 5, the buoyant body has buoyancy such that the water surface reaches the flat surface of the acoustic lens when the ultrasonic transducer is not held by the holding member. An attachment for an ultrasonic transducer, characterized by: In this way, when the ultrasonic transducer is held by the holding member, the acoustic radiation surface of the ultrasonic transducer is reliably brought into contact with liquid (in this case, with water). Irradiation is not obstructed.

Reference Signs List 1 ice 2 hole in ice 10 ultrasonic transducer 10a acoustic radiation surface 11 cable 12 ultrasonic vibrator 23 bottom surface of ultrasonic transducer 24 perimeter of ultrasonic transducer Surface 25 Grooves 30, 60 Attachments 31, 61, 91, 111 Holding members 32, 62 Bottoms of holding members 41, 121, 131, 141 Horizontal maintenance tools 42, 133, 143 as horizontal maintenance means Frame Body 45 Long screws 61a and 91a as rod-shaped members Bottom surface 66 of holding member Fitting hole 67 Water supply/discharge hole 71 Buoyant body as horizontal maintenance means 81 Acoustic lens 82 Flat surface 83 Convex surface 101 Attachment Fixing tool 114...Screw 142 as a fastening member...Side part C2...Center of frame

Claims (10)

An attachment that is suspended from a cable and accommodates an ultrasonic transducer that transmits and receives ultrasonic waves in a molded state, and is attached to an ultrasonic transducer for a fish finder whose bottom surface is an acoustic radiation surface. ,
an acoustic lens having a flat surface and an opposite convex surface;
The ultrasonic transducer is attached and detached so that the acoustic lens is held with the flat surface facing upward and the acoustic radiation surface is acoustically connected to the flat surface of the acoustic lens. a retaining member capable of retaining;
An attachment for an ultrasonic transducer, comprising horizontal maintenance means for horizontally maintaining the ultrasonic transducer and the acoustic lens. 2. The horizontal maintenance means according to claim 1, wherein said horizontal maintenance means is a horizontal maintenance device installed in an opening of a hole provided in the ice to horizontally maintain said ultrasonic transmitter/receiver and said acoustic lens. Attachment for ultrasonic transducer. The horizontal maintenance instrument comprises a frame body having a plurality of sides,
A rod-shaped member that connects the horizontal maintenance device and the holding member is arranged at a position shifted from the center of the frame,
3. An attachment for an ultrasonic transducer according to claim 2, wherein said holding member is arranged inside said frame. The attachment for an ultrasonic transducer according to claim 2 or 3, characterized in that said horizontal maintenance device is made of a frame body having an even number of sides of 4 or more and is foldable. The horizontal maintenance means is provided so as to surround the holding member from the outer peripheral side, is made of a material whose specific gravity is smaller than that of water, and maintains the ultrasonic transducer and the acoustic lens horizontally by buoyancy acting on itself. 2. An attachment for an ultrasonic transducer according to claim 1, characterized in that it is a buoyant body that floats. 6. The method according to any one of claims 1 to 5, wherein the acoustic lens is detachably held with respect to the holding member and is selected from a plurality of types of acoustic lenses having at least one of different dimensions and shapes. An attachment for an ultrasonic transducer according to any one of claims 1 to 3. A fitting hole is provided in the bottom of the holding member for fitting the convex surface side of the acoustic lens with the flat surface facing up so as to protrude downward from the bottom surface of the holding member,
7. An attachment for an ultrasonic transducer according to any one of claims 1 to 6, wherein said fitting hole has a shape whose inner diameter gradually increases as it goes upward. A fitting hole is provided in the bottom of the holding member for fitting the convex surface side of the acoustic lens with the flat surface facing up so as to protrude downward from the bottom surface of the holding member,
7. The acoustic lens according to any one of claims 1 to 6, further comprising a mounting fixture that is fixed to the inner peripheral side of the holding member and presses the flat surface of the acoustic lens that is fitted in the fitting hole. Attachment for ultrasonic transducer. a fitting hole for fitting the convex surface side of the acoustic lens with the flat surface facing up into the bottom portion of the holding member so as to protrude downward from the bottom surface of the holding member; a water supply/discharge hole for supplying and discharging water in the holding member;
The water supply/discharge hole is formed by widening a part of the fitting hole,
7. The ultrasonic transducer according to any one of claims 1 to 6, wherein the acoustic radiation surface of the ultrasonic transducer and the flat surface of the acoustic lens are acoustically coupled via water. Attachment for sonic transducers. A groove portion extending in a circumferential direction of the ultrasonic transducer is formed in an outer peripheral surface of the ultrasonic transducer, and a fastening member passing through the holding member is fitted into the groove portion. Item 10. An attachment for an ultrasonic transducer according to any one of Items 1 to 9.

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